Antenna



Patented Nov. 28, 1939 UNITED, STATES ANTENNA Werner Buschbeck, Berlin,Germany, assignor to Telefunken Gesellschaft fiir Drahtlose Telegraphiem. b. H., Berlin, Germany, a corporation of Germany Application March12,

j Germany March 8, 1937 6 Claims.

This invention relates to an arrangement for matching a short-waveantenna whose length canbe adjusted with an energy line.

The invention relates to an improvement'in the matching arrangementdescribed in my copending application No. 168,120, filed October 9,1937. The subject matter of the co-pending application is a line sectioninserted between the energy line and an'antenna 'whose length is sovaried that it is always equal to a quarter wave and the said length ofthe linesection is likewise varied with theantenna length to alwaysequal a quarter wave, while its wave resistance is equal to thegeometrical mean value between the wave resistance of the energy lineand that of the bottom point of the antenna. The accompanying figureshows a practical embodiment of the presend invention. As shown in thefigure, the tubular antenna l is to be mechanically supported againstthe outer conductor 3 by an insulator 1 at the lower end of which theantenna is pulled over the inner conductor 5 of the energy line. Thisinsulator is fixedly secured to the lower end of the antenna, so thatwhen the length of the antenna changes, the insulator moves in the outertube 3. The insulator must be dimensioned with respect to mechanicalconsiderations and must be very strong. This entailsa considerableincrease in the capacity at the place at which the antenna conductor ofthe energy line joins the inner conductor of the energy line.

In accordance with .the invention, the effect of this capacitiveincrease will be compensated in that at the place at which thetransformation provided an insulator 8 of a size corresponding toinsulator 1. The invention is based upon the known fact that a wattlessresistance placed at a line appears at a distance equal to a quarterwave with its reciprocal value. Since the transformer section hasalength always equal to a quarter wave, this fact can, in accordancewith the invention, be utilized successfully at any desired tuning ofthe antenna for compensating the disturbing insulator capacity. Asviewed from the cable the efiects of the insulators 1 and B eliminateeach other at the input of the transformation piece, so that the entirearrangement operates as if no insulators were present. The insulator 8remains fixed at the same place while the insulator 1 moves with theantenna conductor I such that the distance between the insulators isequal to a quarter wavelength.

I claim:

1. A short wave antenna system comprising a piece joins the actuallead-in cable, there is again 1938, Serial No. 195,431

variable length vertical aerial conducting tube adjustable to haveganeffective free length equal to an odd multiple including unity ofone-quarter of the length of the operatingwave, a vertical concentricline section having an outer conductor 5 and inner conductor, saidaerial tube being arranged to-slide over andcontac-t the inner conductorof said line, an energy feeder also in the form of a concentric linecoupled to the bottom of said vertical concentric line section thelength 10 of said-inner conductor of said line section as measured fromsaid feeder to the nearest point of contact with said aerial tube beingsubstantially equal to the efiective free length of said aerial, aninsulator attached to said aerial tube 15 and movable therewith spacingsaid tube from said outer conductor, and a second insulator between saidinner conductor and said outer conductor arranged at a distance equal toa quarter of the length of the operating wave from said 20 firstinsulator and so dimensioned that the capacity effect of said firstinsulator is compensated thereby.

2. A short wave antenna system comprising a vertical aerial conductingtube adjustable to an 25 odd multiple including unity of a quarter wavelength, a concentric line transformer section having an outer conductorand an inner conductor, said aerial tube being arranged to slide overand contact the inner conductor of said section, a 30 first insulatorattached to the lower end of said aerial tube and movable therewith tospace said tube from said outer conductor the length of said innerconductor between the'end of said aerial tube and the bottom of thetransformer section 35 being constantly equal to the effective freelength of the aerial tube, and a second insulator at the bottom of saidtransformer section so dimensioned that the capacity efiects of saidfirst insulator are compensated thereby. 4o 3. A short wave antennasystem comprising a variable length aerial conductor adjustable to havean effective free length equal to an odd multiple including unity ofone-quarter of the length of the operating wave, a' feeder and a line 4having a length equal to the effective free length of said aerialconductor connecting said feeder to said aerial conductor, saidconductor being slidable over said line whereby a change of length ofsaid aerial conductor simultaneously changes 50 the length of said linein equal amount, an insulator surrounding the end of said aerialconductor surrounding said line, a second similar insulator at the endof said line remote from said aerial conductor whereby the capacityeffect of 55 said first insulator is compensated for by said secondinsulator.

4. A short wave antenna system comprising a variable length aerialconductor adjustable to have an efiective free length equal to an oddmultiple including unity of one-quarter. of the length ,of the operatingwave, a concentricline feeder and a concentric line matching sectionhaving a length equal to the effective free length of said aerialconductor connecting said feeder to said aerial condu'ct'or, saidsection having an outer sheath and an inner conductor, said aerialconductor being slidable over said inner conductor whereby a change oflength of said aerial conductor simultaneously changes the effectivelength of said matching section in equal amount, an insulatorsurrounding the end of said aerial conductor surrounding said centralconductor, a second similar insulator at the end of said matchingsection remote from said aerial conductor, said second insulator beingso dimensioned that the capacity efiect of said first insulator iscompensated thereby.

5. A short wave antenna system comprising a variable length verticalaerial conductor tube adjustable to have an efiective freelength equalto an odd multiple including unity of one-quarter of the length of theoperating wave, a vertical concentric line section having an outerconductor and inner conductor, said aerial tube being arranged to slideover and contact the inner conductor of said line, an energy feeder alsoin the form of a concentric line coupled to the bottom of said verticalconcentric line section the length of said inner conductor of said linesection as measured from said feeder to the nearest point of contactwith said aerial tube being substantially equal to the effective freelength of said aerial, an insulator attached to said aerial tube andmovable therewith spacing said tube from said outer conductor, and asecond insulator similar to said first insulator between said innerconductor and said outer conductor arranged at a distance equal to theefiective free length of said aerial whereby the capacity effect of saidfirst insulator is compensated thereby.

6. A short wave antenna system comprising a vertical aerial conductortube adjustable to an odd multiple including unity of a quarter wavelength, a concentric line transformer section having an outer conductorand an inner conductor, said aerial tube being arranged to slide overand contact the inner conductor of said section,a first insulatorattached to the lower end of said aerial tube and movable therewith tospace said tube from said outer conductor the length of said innerconductor between the end of said aerial tube and the bottom of thetransformer section being constantly equal to the effective free lengthof the aerial tube, and a second similar insulator at the bottom of saidtransformer section whereby the capacity effects of said first insulatorare compensated thereby.

WERNER BUSCHBECK.

